Background: Emphysematous renal tract disease (ERTD) is a rare necrotizing infection of the renal parenchyma and urinary tract caused by gas-producing organisms. ERTD deserves special attention because of its life-threatening potential. Objectives: To study the clinical features, radiological classification and prognostic factors of ERTD; and to compare the modalities of management and the outcome among the various radiological classes of ERTD. Patients and Methods: Twenty consecutive patients with diabetes and ERTD, seen over last 3 years in a tertiary care institute of north India, were included in the study. All patients were subjected to computerized tomography (CT) after initial diagnosis by ultrasonography. They were classified into 5 classes as previously described. All patients included in the study were conservatively managed with appropriate antibiotics and/or percutaneous drainage or surgery if required. Result: Mean age (+/- SD) of these subjects was 54.4 +/- 20.6 years; duration of diabetes mellitus 8.6 +/- 5.8 years, and duration of symptoms related with ERTD ranged from 3 days to 3 months. Two patients had isolated emphysematous cystitis, 13 patients had emphysematous pyelonephritis (EPN), 3 had both EPN and cystitis, and 1 patient had EPN with cholecystitis, and 1 patient had EPN with pyomyositis. Only 7 (35%) patients had a history of pneumaturia. Escherichia coli was the commonest microorganism. The radiological distribution in 18 (2 had isolated cystitis) patients with EPN was: 2 patients had class 1; 1 had class 2; 2 had class 3A; 11 had class 3B, and 2 had class 4. Of 20 patients 11 (55%) survived. However, those patients who died had severe EPN based on radiological class (6 had class 3B and 1 had class 4). There was no significant difference between the survivor and non-survivor groups with respect to age, gender, duration of diabetes mellitus, duration of symptoms, serum creatinine level, total leukocyte count, hemoglobin, platelet count and culture positivity. Conclusion: Computerized tomographic class 3B or 4 is the most reliable predictor of outcome in patients with ERTD. Copyright (c) 2007 S. Karger AG, Basel.